The prominent civil rights leader who founded the National Organization for Women (NOW) in 1966 is Betty Friedan. She is best known for her book "The Feminine Mystique," which challenged traditional gender roles and inspired the second-wave feminist movement in the United States. Friedan's leadership within NOW aimed to advocate for women’s rights, including workplace equality, reproductive rights, and the right to choose. Her work played a significant role in shaping public discourse around gender issues.